Iowa State University Veterinarian Records, RS 22/6/0/9, University Archives, Special Collections Department, Iowa State University, http://www.add.lib.iastate.edu/spcl/arch/rgrp/22-6-0-9.html
'On July 30, 1940, a call came in concerning a four-year-old sorrel mare which the owner had diagnosed as having "colic". Upon arrival at the farm, the following history was given. The mare had been on a bundle-wagon hauling loads for a long distance over soft ground. Apparently the horse was normal until she reached the threshing machine, where she fell. They immediately unhitched her and, noting the unilateral epistaxis, claimed that the mare had hit the machine with her head. The mare soon arose and was led to a nearby grove. There had been no change in the feed.
Kufrin, R. Steven
"Ruptured Lung in a Horse,"
Iowa State University Veterinarian: Vol. 3
, Article 7.
Available at: https://lib.dr.iastate.edu/iowastate_veterinarian/vol3/iss1/7